The general objective of the proposed research is to model in the rat the disordered attention seen in schizophrenic patients. By means of electrical and chemical stimulation to various sites in the brain we hope to better understand the central mechanisms associated with the mediation of attentional processes. The study of the effects of antipsychotic drugs on this modeled behavior in the rat will give, at the least, information concerning the specific action of these drugs on behavior, and at the most, specific insights into the manner by which these drugs achieve their therapeutic effects. The second aspect of this proposal involves the study of the effects of neuroleptic drugs and drugs that have been thought to model human psychoses (e.g., amphetamine, cocaine, phencyclidine) on intracranial self stimulation thresholds. Since many of the areas of the brain that have been implicated as sites of action of the neuroleptic drugs also support self stimulation, the use of this procedure should allow direct analyses of the role of these areas of the brain in the mediation of drug effects on behavior.